Pulper defibering means



April 1967 R. J. SARGOOD 3,314,6fl7

PULPER DEFI BERING MEANS Filed Jan. 29, 1964 5 Shedsheet 1 @l I l ,O\ II y I '2 FIG! H .4 16

' l8 I I r I- i 1 22 2O. m

FIGZ l6 I NVEN TOR.

RICHARD J. SARGOOD BY ATTORNEYS April 18, 19s? PULPER DEFIBERING MEANSFiled Jan. 29, 1964 I N VEN TOR.

RICHARD J. SARGOOD F168 BY ATTURN EYS R. J. SARGOOD 3,314,61 7

s Sheets-Sheet 2 April 18, 1967 R. J. SARGOOD 3,314,617

PULPER DEFIBERING MEANS Filed Jan. 29, 1964 3 Sheets-Sheet 5 FIGIZ I NVEN TOR.

RICHARD J. SARGOOD BY ATTORNEYS United States Patent 3,314,617 PULPERDEFIBERIN G MEANS Richard .I. Sargood, Hoosick Falis, N.Y assignor toThe Noble 8: Wood Machine (10., Hoosicir Falls, N.Y., a corporation ofNew York Filed Jan. 29, 1964, Ser. No. 340,864 2 Claims. (Cl. 241-260)This invention relates to machinery for pulping paper stock and moreparticularly to improved defibering means mounted on rotor and statorelements of a pulper. A pulping machine of this class is described in W.C. Tomlinsons pending application, Ser. No. 73,671, filed December 5,1960, now abandoned.

With the arrangement shown in the above said pending application, acombined pulping and defibering action is obtained in which the stock iscirculated in the pulping tank, subjected to pulping blade action, andwithdrawn from the tank through an annular outlet orifice in the tankbottom between the rotor and stator elements of the pulper. In thisannular orifice, opposed defibering teeth or equivalent defiberingelements additionally defi'ber the stock as it passes therethrough.

The significant features of the prior constructions, as they relate tothe present invention, principally concern the type of defibering actiontaking place in the outlet orifice and the effect of this action interms of dulling and eroding wear on the defibering elements. It will beunderstood that the opposed defibering teeth in the annular orifice arenot spaced closely together as in the typical jordans, beaters or discrefiners of the prior art, but instead are spaced apart so that thedefibering action takes place primarily on the larger stock particles.Of course, the rapidly fluctuating pressure waves created by the teethof the rotor in moving past the opposed teeth of the stator, despite thespacing therebetween, cause hydraulic shear which acts to some extent onall stock particles in the orifice. With the arrangement and spacingshown, however, the direct, cutting type of contact of a typical refinertakes place only when relatively large particles enter the orifice.These factors are highly significant in the context of the presentinvention because they determine the type of wearing or eroding actionon the teeth. With the arragement shown, the teeth Wear primarily ontheir leading edges and from the top down. Thus, after a period ofextended use, the entry to the annular orifice becomes slightly widened,and the leading edges of the opposed teeth become rounded off.

The present invention has as a primary object the provision of means forextending the useful life of the defibering elements in the annularorifice.

In the accomplishment of this object in a preferred embodiment of myinvention, I provide a plurality of removable and reversible defiberingteeth segments for mounting on the rotor and stator in the annularorifice. These segments are symmetrically constructed with relation totheir mounting means and their Working surfaces so that they can beeasily removed, turned upside down, and remounted.

Accordingly, it is a feature of my invention that, once the teeth havebecome worn in their upper portions and along their leading edges, thesegments can be removed and turned over. This action causes therelatively sharp, previously trailing edges, to become the leadingedges, and the relatively unworn, previously lower teeth portions tobecome the upper portions.

It is a further feature of my invention that the relatively milddefibering action in the orifice permits the teeth segments to besecured by standard machine screws without the requirement of woodenspacers, retaining bands or the like, which are required in jordans and3,314,617 Patented Apr. 18, 1967 heaters in which the refining actioncreates far more stress and strain.

Other objects and advantages of the invention will become apparent froma study of the accompanying drawings and descriptive matter in which isillustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a front elevation of a corporating the invention;

FIG. 2 is a view in perspective of the rotor element of the pulpershowing the teeth segments mounted on the periphery thereof;

FIG. 3 is a view in perspective of the stator element showing the teethsegments mounted on the inner circumference thereof:

FIG. 4 is a view in perspective of the rotor and stator elements inassembly with the teeth segments defining an annular outlet orificetherebetween;

FIGv 5 is an elevational View in section showing the mounting of theteeth segment assembly on the rotor and stator elements;

FIG. 6 is a fragmentary plan view of the rotor and stator elementsshowing the spacing between the opposed teeth segments;

FIG. 7 is a fragmentary front elevation of the teeth segment which ismounted on the rotor element;

FIG. 8 is a fragmentary front elevation of the teeth segment which ismounted on the stator element;

FIG. 9 is a view in perspective of the teeth segment of FIG. 7;

FIG. 10 is a view in perspective of the segment holder on which theteeth segment of FIG. 9 is directly mounted;

FIG. 11 is an exploded elevational View in section of a portion of therotor element, the segment holder and the teeth segment;

FIG. 12 is a diagrammatic plan view of a small portion of the teethsegment showing by dotted lines the wear which occurs on the leadingedges of the teeth; and

FIG. 13 is an elevational view in section of a portion of the rotorelement, the segment holder and the teeth segment, showing by a dottedline the wear on the teeth segment which occurs from the top down.

Referring now more particularly to the drawings, FIG. 1 shows thepulper, generally designated as 10, having a tank 12 preferably madefrom mild steel, stainless steel, cast iron or tile. The tank has agenerally horizontal bottom wall 14 in the center of which a circularrotor element 16 is mounted for rotation. Rotor element 16 is fixed to ashaft 18 which is supported in suitable bearings 20. The shaft 18 andassociated rotor element 16 are driven by an electric motor and beltdrive system indicated generally at 22.

Mounted on the rotor element 16, and extending tangentially from theshaft 18 are a multiplicity of impeller blades 24, usually six innumber. Rapid rotation of the rotor element 16 and its impeller blades24 causes previmove violently within causes the larger particles ofstock to break down. Simultaneously, forces are pulping machine intosize, and thereafter fall back for further pulping.

The smaller pieces of stock, which comprise the more finished pulp, arenot as easily caught up in the vortex field and tend to flow radiallyfrom the rotor center. In order to assist this tendency,-a plurality oflateral ejector blades 26 having a right-angled shape are mountedverrotor element coaxial with the shaft 18.

In operation, rotor element 16, impeller blades 24 and ejector blades 26cooperate to throw the larger stock upward in the tank and to push themore finished pulp radially along the tank bottom 14.

In order to withdraw the more finished pulp from the pulper before it isagain intermixed with the larger pieces of stock, an annular outletorifice, indicated generally at 28, is provided between rotor element 16and tank bottom wall 14. The annular outlet orifice 28 is created byconstructing the bottom wall 14 with an inner circumference of greaterradius than that of the outer circumference of rotor element 16. Thus,when the rotor element 16 is in assembly, an annular outlet orifice willbe formed between rotor element 16 and tank bottom wall 14. The morefinished pulp not only falls into this annular outlet orifice 28 as itpasses radially over the rotor element 16, but is also drawn into theorifice by suction forces created by the discharge pump and by therotation of the rotor element \16 in close proximity to the bottom wall14.

The facing peripheries of the rotor and stator elements have mountedthereon defi'bering means including a plurality of defibering teethsegments 30. The interaction of these teeth segments reduces the largerparticles of pulp stock to the desired size as they pass through theannular orifice 23. It will be seen in FIGS. 2 and 3 that the rot-orelement 16 and the stator element 14 each have eight teeth segmentsmounted on their facing periphcries. One difference between the teethsegments 30 is that the segments mounted on the rotor element have aconvex shape whereas the segments mounted on the stator element have aconcave shape. Another difference is the segment tooth angle. FIG. 7shows the tooth angle of the rotor-mounted segment to be approximately 4from the vertical. FIG. 8 shows the tooth angle of the statorrnountedsegment to be vertical. This tooth angle combination has proven to bequite satisfactory for defibering purposes although the invention is notlimited thereto. Except for the oppositely curved shapes and thediffering teeth angles, the teeth segments 30 are identical. Therefore,the teeth segments mounted on r-otor element 16 will be described indetail, but it will be understood that the stator-mounted segments areessentially similar.

In the preferred embodiment, a teeth segment assembly is composed of ateeth segment 30 shown in FIG. 9, and a segment holder 32 shown in FIG.10. The teeth segment is attached to the segment holder which is itselfattached to the rotor element periphery. Preferably, eight teeth segmentassemblies are mounted around the rotor. It will be seen in the explodedview of FIG. 11 that segment holder 32 has a right angled configurationwith an upper horizontal portion 34 and a vertical portion 36. Thesegment holder is threadably secured to rotor element 16 by bolts 38,usually three in number, which are flush fitted into the upper surfaceof horizontal portion 34'.

A lip 42 is formed at the lower edge of the front surface 44 of segmentholder 32. Lip 42 has an upper lip surface 46. Threaded screw receivingbores 48, usually four in number, are formed in the vertical portion 36.Each bore 48 is precisely located halfway between upper :surface 40 ofhorizontal portion 34 and upper lip surface '46. That is, a horizontalplane passing through the axes of bores 4t} would precisely divide orbisect the front surface 44 of segment holder 32 into two equal areashaving equal vertical dimensions.

Each teeth segment 30 has substantially vertical teeth 59, milled inrib-like fashion, which extend from the upper surface 52 to the lowersurface 54 of the segment. Other tooth shapes may alternatively beemployed. A teeth bed 56 forms the integral backing or foundation forteeth and has a rear curved surface 58. Rear surface 58 of teeth segment30 and front surface 48 of the segment holder 32 are mirror images whichare shaped to fit closely together. countersunk bores 60 are formedthrough teeth bed 56 in alignment with screw receiving bores 48. Machinescrews 62, preferably made from stainless steel, threadably secure teethsegment 30 to segment holder 32. Upper lip surface 46 of lip 42 abutslower surface 54 of segment 30 and gives added vertical support andstability to the segment. It will be seen in FIG. 5 that the segmentholder mounted on the rotor element 16 has a slightly differentconstruction from that of the segment holder mounted on the statorelement in that the stator segment holder has no lip 42 but rather has alower surface 64 formed flush with lower surface 54 of teeth segment 35The segment support provided by the lip of the rotor-mounted segmentholder is instead provided by rim 66 of the stator element. Thisdifference is merely a matter of design choice in the illustratedpreferred embodiment and is not critical to the functioning of theinvention.

It will now be appreciated that teeth segment 30 is constructed so thatits teeth 50 and mounting bores 60 are symmerically located with respectto a horizontal plane bisecting the teeth segment. That is, revolvingthe teeth segment about an axis normal to a central point on segmentrear surface 58 would not change the relative location of the teeth 50and the bores 60.

This symmetrical construction permits the teeth segments to be used onthe pulper for a substantially longer time period of use because afterthe segments have become worn, they can be detached, flipped over,reattached and used further. To be more specific, wear on the teethsegments occurs in two areas. FIG. 12 shows a teeth segment 30 which,when mounted on rotor element 16, is revolved in a counter-clockwisedirection (i.e. to the left). The leading edges of each tooth 50 becomeworn as illustrated by the dotted lines. FIG. 13 shows an elevation ofFIG. 12 and illustrates the teeth wear which occurs from the top down.The combination of teeth wear on the leading edges and from the top downeventually permits larger stock particles to pass through the enlarged:annular orifice without being sufficiently defibered or without beingproperly defibered. Eitherresult is undesirable.

By constructing the segments in the described sym- 'metrical fashion,the segments, when worn, can be detached, flipped over and remountedwhereby the still sharp previously trailing teeth edges become theleading edges and the still unworn previously bottom teeth portionsbecome the top portions.

In operation, after the teeth segments have become worn as described,the segment holders 32 are detached from rotor element 16 and statorelement 14 by unbolting bolts 38 and lifting the segment holders andtheir associated teeth segments 30 from the rotor and stator. The teethsegments 30 are then easily detached from the segment holders 32 byremoving screws 62 with a screwdriver or an Allen wrench. The teethsegments 30 are then flipped over so that upper surface 52 isrepositioned as lower surface 54 after which the teeth segments arereattached by screws 62 to the segment holders 32. The segment holdersare then rebolted to rotor element 16 and stator element 14, placing thepulper in assembled condition for further pulping.

This interchange of position should, under usual pulping conditions,result in an extension in the time period of teeth segment use ofapproximately 50-70% which obviously constitutes a considerablefinancial savings.

Obviously, many modifications and variations of the present inventionare possible in light of the above teach ings. Therefore, it is to beunderstood that the invention is not limited in its application to theconstruction and arrangement of parts specifically described orillustrated, but is to be limited only by the spirit of the inventionand the scope of the appended claims.

I claim:

1. In a pulper of the type having a tank with a bottom wall stator,vertical stator walls forming a central circular opening in said bottomwall stator, a rotor mounted for rotation within said central opening,blades mounted on said rotor for pulping the stock, the periphery ofsaid rotor and said vertical stator Walls defining between them anannular outlet orifice through which the .pul-ped stock is withdrawn,the improvement therein comprising; a plurality of cooperating opposeddefibering teeth segments having substantially vertical ribs formedtherein and walls forming horizontal mounting holes, said teeth segmentsdetachably mounted on said rotor and said stator for defiberingoversized particles of stock, said ribs and hole walls of said teethsegments being shaped and located symmetrical to an imaginary planehorizontally bisecting said teeth segments whereby after extensive usehas worn said teeth segment ribs, said teeth segments are detached,radially revolved 180, and reattached to permit further use.

2. In a pulper of the type having a tank with a bottom wall stator,vertical stator walls forming a central circular opening in said bottomwall stator, a rotor mounted for rotation within said central opening,blades mounted on said rotor for pulping the stock, the periphery ofsaid rotor and said vertical stator Walls defining between them anannular outlet orifice through which the pulped stock is withdrawn, theimprovement therein comprising; a plurality of cooperating opposeddefibering teeth segments having substantially vertical ribs formedtherein and walls forming horizontal mounting holes; a plurality ofsegment holders on which said teeth segments are detachably mounted,said segment holders mounted on the periphery of said rotor and theinner circumference of said stator, said teeth segment ribs and mountinghole Walls symmetrically formed and located with relation to ahorizontal plane bisecting each said teeth segment whereby afterextensive use has worn said teeth segment ribs, said teeth segments canbe detached from said segment holders, revolved about an axis normal tothe segment teeth face, and reattached to said segment holders toprovide for a subsequent period of teeth segment use.

References Cited by the Examiner UNITED STATES PATENTS 1,794,972 3/1931Mayer 241260 X 2,369,312 2/1945 Porteous 146l84 X 2,484,509 10/1949Hopkins 241-257 X 2,577,716 12/1951 Shelton 241260 X 2,645,982 7/1953CoWles 241-257 2,838,981 6/1958 Dent 241257 X 3,009,659 11/1961 Jones241260 X WILLIAM W. DYER, 111., Primary Examiner. ROBERT C. RIORDON,Examiner. H. F. PEPPER, Assistant Examiner.

2. IN A PULPER OF THE TYPE HAVING A TANK WITH A BOTTOM WALL STATOR,VERTICAL STATOR WALLS FORMING A CENTRAL CIRCULAR OPENING IN SAID BOTTOMWALL STATOR, A ROTOR MOUNTED FOR ROTATION WITHIN SAID CENTRAL OPENING,BLADES MOUNTED ON SAID ROTOR FOR PULPING THE STOCK, THE PERIPHERY OFSAID ROTOR AND SAID VERTICAL STATOR WALLS DEFINING BETWEEN THEM ANANNULAR OUTLET ORIFICE THROUGH WHICH THE PULPED STOCK IS WITHDRAWN, THEIMPROVEMENT THEREIN COMPRISING; A PLURALITY OF COOPERATING OPPOSEDDEFIBERING TEETH SEGMENTS HAVING SUBSTANTIALLY VERTICAL RIBS FORMEDTHEREIN AND WALLS FORMING HORIZONTAL MOUNTING HOLES; A PLURALITY OFSEGMENT HOLDERS ON WHICH SAID TEETH SEGMENTS ARE DETACHABLY MOUNTED,SAID SEGMENT HOLDERS MOUNTED ON THE PERIPHERY OF SAID ROTOR AND THEINNER CIRCUMFERENCE OF SAID STATOR, SAID TEETH SEGMENT RIBS AND MOUNTINGHOLE WALLS SYMMETRICALLY FORMED AND LOCATED WITH RELATION TO AHORIZONTAL PLANE BISECTING EACH SAID TEETH SEGMENT WHEREBY AFTEREXTENSIVE USE HAS WORN SAID TEETH SEGMENT RIBS, SAID TEETH SEGMENTS CANBE DETACHED FROM SAID SEGMENT HOLDERS, REVOLVED 180* ABOUT AN AXISNORMAL TO THE SEGMENT TEETH FACE, AND REATTACHED TO SAID SEGMENT HOLDERSTO PROVIDE FOR A SUBSEQUENT PERIOD OF TEETH SEGMENT USE.